The invention relates to a surgical tubular-shafted instrument comprising a tubular shaft and a gripping part connected thereto, a tool pivotable about an axis of rotation extending transversely to the longitudinal axis of the shaft, and a push element in the shaft, the push element being movable by the gripping part in the longitudinal direction of the shaft and being in engagement with the tool by means of projections and recesses arranged in spaced relation to the axis of rotation of the tool such that the tool is pivotable about its axis of rotation upon displacement of the push element.
Such surgical tubular-shafted instruments are known, for example, from U.S. Pat. No. 5,509,923. For pivotal movement of the two parts of the tool, these carry a toothed segment which meshes with an elongate toothed segment on the push element and thus transforms the translational movement of the push element into a rotational movement of the tool parts.
Tubular-shafted instruments of this kind often have a very small diameter and, therefore, it is difficult to achieve the necessary stability with such small diameters. With such tubular-shafted instruments, it thus often proves impossible to generate the desired closing forces for the tool.
With the known tubular-shafted instrument construction, there is, in particular, the danger that the operative connection between the projections and the recesses will become disengaged by deformation of the material used. The meshing projections and recesses may "snap out" or become completely disengaged.